Grasping for Light of Distant Worlds

By DENNIS OVERBYE

Published: June 22, 2004

HALEAKALA, Hawaii - Few sights in science are sadder than astronomers standing in the rain.

Dr. Ben R. Oppenheimer and his associates slouched along the front porch of their rented house here late one afternoon, staring out from under the roof across the lawn and down the slopes of Haleakala, the dormant volcano that makes up the eastern two-thirds of the island of Maui.

In the distance, past the trees and flowers, and nearly a mile downhill, sunlight was skipping off Kihei Bay, turning it to molten gold. But here, almost halfway to the top of Haleakala, raindrops were sighing out of the air. Uphill in the other direction, the 10,000-foot summit was shrouded in black clouds, auguring doom for the night's astronomical prospects.

Dr. Oppenheimer, then a 31-year-old staff astronomer at the American Museum of Natural History and dressed like the New Yorker he is, completely in black, smiled grimly.

"Maybe I could learn to surf," he said. "I actually love this kind of weather, just not when I'm trying to see through it."

For three weeks, he and his colleagues had been commuting every night from their house up the winding road to the summit and a United States Air Force observatory where they were hoping to make history by recording the first images of planets around other stars.

It was a groundbreaking project, the first run for an experimental new camera, designed to ferret the dim light of distant planets out of the glare of their home stars, and one of the first chances for civilian astronomers to conduct deep space research with a sophisticated high-resolution Air Force telescope originally built to spy on spy satellites and other Earth-orbiting objects.

The sighting of a new planet will be one of the signal events in the history of astronomy and science - a place to study, to better understand Earth and, perhaps, one day to travel.

That they are Out There to be seen is beyond dispute. Over the last decade, astronomers have deduced the existence of more than 100 extrasolar planets, mostly from the wobbles that their gravitational fields induce in the motions of their home stars. All are giants, the mass of Jupiter or greater, orbiting far closer to their stars than Jupiter does to the Sun, and extremely unlikely abodes for life. But many more planets, including smaller ones more like Earth, may lurk undetected in these systems.

Yet until astronomers can actually "see" these worlds by recording and analyzing their light, the questions of what these planets are made of, what the conditions are there and whether there are continents or weather or respirating organisms on them will remain in the realms of mystery and science fiction. NASA is planning a series of satellites in the next couple of decades, culminating in the Terrestrial Planet Finder, to do just that in a systematic way.

Dr. Oppenheimer and his colleagues are, therefore, blazing a path that will be trod by more astronomers in the next few years, as the technology of telescopes and cameras continues to improve and scientists ramp up for the planet finder.

But right then it was raining.

Behind every discovery that winds up in the headlines, there is invariably a long chain of trial and error, disappointments, failures and delays. Three days on the mountain this spring provided a glimpse of life as astronomers tried to take the first few steps into a new brand of astronomy.

The tale of their effort began in 1999, when the Air Force and the National Science Foundation announced a program to let civilian astronomers use a powerful new telescope on Haleakala.

That telescope, officially the Advanced Electro-Optical System, or AEOS, was completed in 1997. It grew out of the Air Force interest in shooting down satellites with lasers; it is operated by the Directed Energy Directorate of the Air Force Research Laboratory. The AEOS telescope (pronounced EE-ohs) has an ability much prized by potential planet hunters, an advanced system of "adaptive optics" that can tune out the blurring of stars caused by atmospheric turbulence, in principle allowing astronomers on the ground to see parts of the sky in at least as fine detail as the Hubble Space Telescope, which does not have to bother with the atmosphere at all. Removing the blur would make it easier to discern small things like planets in faraway systems.

Dr. Oppenheimer is an old hand at finding small dim things. As a graduate student at the California Institute of Technology in 1995, he helped install a limited system of adaptive optics on the famous 200-inch telescope on Palomar Mountain in Southern California. In what he called "a low-tech version of what we're doing now," he and other astronomers used that system to discover the first example of a type of failed star known as a brown dwarf. It was about 50 times the mass of Jupiter, orbiting another small star in the constellation Lepus.

Planets were the next logical step.

In his pursuit of these planets, Dr. Oppenheimer has pulled together an eclectic cast of people and instruments from several institutions, including Cornell, the University of Hawaii, the University of California at Berkeley, the California Institute of Technology and Boeing, as well as the Museum of Natural History. Dr. Oppenheimer described his team's efforts as "baby steps" in the direction that the planet finder would go.